# Support for HD44780 (20x4 text) LCD displays
#
# Copyright (C) 2018  Kevin O'Connor <kevin@koconnor.net>
# Copyright (C) 2018  Eric Callahan <arksine.code@gmail.com>
#
# This file may be distributed under the terms of the GNU GPLv3 license.
import logging

BACKGROUND_PRIORITY_CLOCK = 0x7fffffff00000000

HD44780_DELAY = .000037

class HD44780:
    char_right_arrow = '\x7e'
    char_thermometer = '\x00'
    char_heater_bed = '\x01'
    char_speed_factor = '\x02'
    char_clock = '\x03'
    char_degrees = '\x04'
    char_usb = '\x05'
    char_sd = '\x06'
    def __init__(self, config):
        self.printer = config.get_printer()
        # pin config
        ppins = self.printer.lookup_object('pins')
        pins = [ppins.lookup_pin('digital_out', config.get(name + '_pin'))
                for name in ['rs', 'e', 'd4', 'd5', 'd6', 'd7']]
        mcu = None
        for pin_params in pins:
            if mcu is not None and pin_params['chip'] != mcu:
                raise ppins.error("hd44780 all pins must be on same mcu")
            mcu = pin_params['chip']
            if pin_params['invert']:
                raise ppins.error("hd44780 can not invert pin")
        self.pins = [pin_params['pin'] for pin_params in pins]
        self.mcu = mcu
        self.oid = self.mcu.create_oid()
        self.mcu.add_config_object(self)
        self.send_data_cmd = self.send_cmds_cmd = None
        # framebuffers
        self.text_framebuffer = (bytearray(' '*80), bytearray('~'*80), 0x80)
        self.glyph_framebuffer = (bytearray(64), bytearray('~'*64), 0x40)
        self.framebuffers = [self.text_framebuffer, self.glyph_framebuffer]
    def build_config(self):
        self.mcu.add_config_cmd(
            "config_hd44780 oid=%d rs_pin=%s e_pin=%s"
            " d4_pin=%s d5_pin=%s d6_pin=%s d7_pin=%s delay_ticks=%d" % (
                self.oid, self.pins[0], self.pins[1],
                self.pins[2], self.pins[3], self.pins[4], self.pins[5],
                self.mcu.seconds_to_clock(HD44780_DELAY)))
        cmd_queue = self.mcu.alloc_command_queue()
        self.send_cmds_cmd = self.mcu.lookup_command(
            "hd44780_send_cmds oid=%c cmds=%*s", cq=cmd_queue)
        self.send_data_cmd = self.mcu.lookup_command(
            "hd44780_send_data oid=%c data=%*s", cq=cmd_queue)
    def send(self, cmds, is_data=False):
        cmd_type = self.send_cmds_cmd
        if is_data:
            cmd_type = self.send_data_cmd
        cmd_type.send([self.oid, cmds], reqclock=BACKGROUND_PRIORITY_CLOCK)
        #logging.debug("hd44780 %d %s", is_data, repr(cmds))
    def flush(self):
        # Find all differences in the framebuffers and send them to the chip
        for new_data, old_data, fb_id in self.framebuffers:
            if new_data == old_data:
                continue
            # Find the position of all changed bytes in this framebuffer
            diffs = [[i, 1] for i, (nd, od) in enumerate(zip(new_data, old_data))
                     if nd != od]
            # Batch together changes that are close to each other
            for i in range(len(diffs)-2, -1, -1):
                pos, count = diffs[i]
                nextpos, nextcount = diffs[i+1]
                if pos + 4 >= nextpos and nextcount < 16:
                    diffs[i][1] = nextcount + (nextpos - pos)
                    del diffs[i+1]
            # Transmit changes
            for pos, count in diffs:
                chip_pos = pos
                if fb_id == 0x80 and pos >= 40:
                    chip_pos += 0x40 - 40
                self.send([fb_id + chip_pos])
                self.send(new_data[pos:pos+count], is_data=True)
            old_data[:] = new_data
    def init(self):
        curtime = self.printer.get_reactor().monotonic()
        print_time = self.mcu.estimated_print_time(curtime)
        # Program 4bit / 2-line mode and then issue 0x02 "Home" command
        init = [[0x33], [0x33], [0x33, 0x22, 0x28, 0x02]]
        # Reset (set positive direction ; enable display and hide cursor)
        init.append([0x06, 0x0c])
        for i, cmds in enumerate(init):
            minclock = self.mcu.print_time_to_clock(print_time + i * .100)
            self.send_cmds_cmd.send([self.oid, cmds], minclock=minclock)
        # Add custom fonts
        self.glyph_framebuffer[0][:len(HD44780_chars)] = HD44780_chars
        for i in range(len(self.glyph_framebuffer[0])):
            self.glyph_framebuffer[1][i] = self.glyph_framebuffer[0][i] ^ 1
        self.flush()
    def write_text(self, x, y, data):
        if x + len(data) > 20:
            data = data[:20 - min(x, 20)]
        pos = [0, 40, 20, 60][y] + x
        self.text_framebuffer[0][pos:pos+len(data)] = data
    def clear(self):
        self.text_framebuffer[0][:] = ' '*80

HD44780_chars = [
    # Thermometer
    0b00100,
    0b01010,
    0b01010,
    0b01010,
    0b01010,
    0b10001,
    0b10001,
    0b01110,
    # Heated bed
    0b00000,
    0b11111,
    0b10101,
    0b10001,
    0b10101,
    0b11111,
    0b00000,
    0b00000,
    # Speed factor
    0b11100,
    0b10000,
    0b11000,
    0b10111,
    0b00101,
    0b00110,
    0b00101,
    0b00000,
    # Clock
    0b00000,
    0b01110,
    0b10011,
    0b10101,
    0b10001,
    0b01110,
    0b00000,
    0b00000,
    # Degrees
    0b01100,
    0b10010,
    0b10010,
    0b01100,
    0b00000,
    0b00000,
    0b00000,
    0b00000,
    # USB
    0b01110,
    0b01110,
    0b01110,
    0b11111,
    0b11111,
    0b11111,
    0b00100,
    0b00100,
    # SD
    0b00000,
    0b00111,
    0b01111,
    0b11111,
    0b11111,
    0b11111,
    0b11111,
    0b00000,
]
